Dears, Good day, I have Asus PC with built in window, i am trying to boot recovery mood f9 when the PC start off. unfortunately the recovery not solve the problem even when i select full format for PC. the PC run and shut down again and again (unlimited loop) seems that there is a software problem. i have decided to use a original windows 7 installation file and boot using DVD or USB. but i could not find a way to download windows 7 even when i use Microsoft website and use serial number it gave me a message Error The product key you entered appears to be for software pre-installed by the device manufacturer. Please contact the device manufacturer for software recovery options. How could i get legally ISO file for windows home premium 64 bit ?